Error(s) in re-building vignettes:
--- re-building ‘Enhancements.Rmd’ using rmarkdown

Attaching package: 'knitr'

The following object is masked from 'package:EGRET':

    stitch

dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'Enhancements.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘Enhancements.Rmd’

--- re-building ‘parallel.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'parallel.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘parallel.Rmd’

--- re-building ‘rResid.Rmd’ using rmarkdown
dyld: lazy symbol binding failed: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

dyld: Symbol not found: ____chkstk_darwin
  Referenced from: /usr/local/bin/pandoc (which was built for Mac OS X 10.15)
  Expected in: /usr/lib/libSystem.B.dylib

Error: processing vignette 'rResid.Rmd' failed with diagnostics:
pandoc document conversion failed with error 6
--- failed re-building ‘rResid.Rmd’

--- re-building ‘EGRET.Rnw’ using knitr
--- finished re-building ‘EGRET.Rnw’

SUMMARY: processing the following files failed:
  ‘Enhancements.Rmd’ ‘parallel.Rmd’ ‘rResid.Rmd’

Error: Vignette re-building failed.
Execution halted